Sound waves cannot carry energy through
a water.
b air.
c a mirror.
d a vacuum

Which explanation describes the forces involved for a person to walk down the sidewalk? a. the person's feet push backward on the sidewalk; the sidewalk pushes backward on the person. b. the person's feet push forward on the sidewalk; the sidewalk does not push on the person. c. the person's feet push backward on the sidewalk; the sidewalk pushes forward on the person. d. the person's feet push forward on the sidewalk; the sidewalk pushes forward on the person.

Find v(t), given acceleration a(t)=7j and initial velocity v(0)=k

Smallest intensity of a stimulus that you can detect 50 percent of the time is